Ink jet printers have achieved wide acceptance in the field of printing and continue to make great strides towards high speed, high quality printing. In order to improve the quality and speed of printing, nozzle plates having a larger number of smaller orifices are provided. As the size of the orifices continue to decrease, components of the ink cartridge assembly become increasingly more important. A component of the ink cartridge that is particularly important for proper operation of an ink jet printhead attached to the cartridge is a filter disposed between an ink reservoir and a flow path for ink to the printhead. The filter is the first and most important line of protection for large or foreign particles entering ink flow features of the printheads. Particles larger than the flow features of the printhead can adversely affect the operation of the printhead thus dramatically decreasing the quality and operation of the printhead.
The most widely used filter material for application in an ink cartridge is a Dutch weave stainless steel material. Metal filters are typically attached to a filter assembly in the ink cartridge by hot stamping the metal filter onto a plastic frame using a hot block or hot die. Melted plastic from the frame is squeezed into the filter mesh to create a mechanical interlock between the frame and the filter. However, the cost of such stainless steel material is relatively high.
In order to reduce the cost of the filter and to provide better wetting of the filter during the melting process, synthetic fiber filter materials have been selected for providing filters. Such synthetic fiber materials include acrylics, nylon, polyester, polyethylene, polypropylene, and polyvinylchloride. However, the replacement of metal filter material with synthetic filter materials, makes attachment of the filter to the frame much more difficult. In a hot stamping process, heat must be transferred from the hot block to the filter material and then to the filter frame. If the melting temperature of the frame is lower than that of the filter material, the frame material will be squeezed into the pores of the filter and create a mechanical lock as before. On the other hand, if the melting temperature of the frame is higher than that of the filter material, the filter will be melted and thinned under pressure, and in some cases the stitches around the perimeter of the filter may be damaged thereby weakening the filter.
Ultrasonics may also be used to attach plastic materials to one another. However, when ultrasonics are applied to synthetic filter materials, the high frequency mechanical vibration may cause loose stitches, broken stitches, and particle generation. Loose stitches and broken stitches may cause the filter to fail prematurely. Particle generation may inhibit the flow of ink to and in the ink jet printheads thereby reducing print quality. Another disadvantage of plastic filter materials is that these materials are generally less stiff than metal filter materials and are thus prone to bending, stretching, and wrinkling during the attachment process.
Thus, there continues to be a need for improved low cost filter materials and improved methods for attaching the filter materials to a frame in an ink cartridge for an ink jet printhead.